The use of trays to assist in the separation of constituents in a mixture has long been known in the art. For example, process trays sold under the trademark RIPPLE TRAY used as fractionation trays are described in Hutchinson, U.S. Pat. No.2,767,967; rod tower trays are described in Weeden et al., U.S. Pat. No. 3,414,246; and bubble cap trays are described in Guerrieri, U.S. Pat. No. 3,914,352. See also Perry & Chilton, Chemical Engineer's Handbook, 6th ed., 21-74-21-77, for a general description of perforated-plate or sieve-plate trays.
In supporting trays within the column, support beams are generally mounted in the column and trays are rested upon the support beams and the trays are fastened to the sides of the column. See, Boon et al., U.S. Pat. No. 3,649,466. In Livingston et al., U.S. Pat. No. 4,028,443 circular rings are employed to support the perforated plate.
Although the use of support beams to support trays provides sufficient support to the trays to sustain a given deflection criterion, the use of support beams suffers from both technical and economic disadvantages.
Economically, support beams are physically large, constitute large quantities of materials, are expensive and are difficult to install, especially in revamping an existing column in the field. Technically, support beams typically have the effect of becoming partitions within the columns, thus inhibiting the free movement of process gases through the column and thereby potentially causing deleterious effects upon the process itself. Still further, the use of support beams reduces the active area of the tray because the horizontal flange of the beam blocks the part of the tray which could otherwise be active for process reasons.